In functions that act like constructors there is a mixture of the usage
of `creates` and `constructs`.
Replace all occurrences of `creates` with `constructs` in the first line
of docs of constructor like functions.
A new nightly version (`nightly-2024-08-28`) introduces a few warnings
because of our rustdocs. These are valid warnings and should be fixed,
thanks `clippy` team.
(The `bip152` change is a bit sloppy, open to suggestions.)
Move error code to a private `error` submodule and re-export it at the
crate root.
(Puts private `sealed` module at the bottom of the file i.e., this patch
is strictly a code move but we re-order the code while moving it.)